Fair Value Measurements - Significant Inputs Used in Fair Value Measurement (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business consideration liabilities	$ 42,400	$ 63,800
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business consideration liabilities	$ 42,400	$ 63,800
Level 3 | Discount rate | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input (percent)	0.025
Level 3 | Discount rate | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input (percent)	0.035
Level 3 | Discount rate | Weighted average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input (percent)	31
Level 3 | Probability of payment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input (percent)	1,000
Level 3 | Probability of payment | Weighted average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input (percent)	1,000